This could be a good alternative to travis and I think it is free for public repositories:
"GitHub Actions is available with GitHub Free, GitHub Pro, GitHub Free for organizations, GitHub Team, GitHub Enterprise Cloud, GitHub Enterprise Server, and GitHub AE. GitHub Actions is not available for private repositories owned by accounts using legacy per-repository plans. For more information, see "GitHub's products."
(https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners)
This could be a good alternative to travis and I think it is free for public repositories: "GitHub Actions is available with GitHub Free, GitHub Pro, GitHub Free for organizations, GitHub Team, GitHub Enterprise Cloud, GitHub Enterprise Server, and GitHub AE. GitHub Actions is not available for private repositories owned by accounts using legacy per-repository plans. For more information, see "GitHub's products." (https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners)